As one of the most common clinic symptoms, insomnia is an originating and continuous disorder of sleep, rendering the sleep quality insufficient for normal physiological requirements of human body, thereby affecting the usual activities of patients, causing sleep disorder syndrome with symptoms like weariness, attention deficit and lags in response.
Hypnotic drugs are drugs which help people to sleep, and ideal requirements on this class of drugs include: (1) reducing the time to fall asleep, i.e., reducing sleep induction period; (2) elongating sleeping time and increasing the depth of sleep; (3) the ratio of slow wave sleep phase and rapid eye movement phase remaining unchanged. Sedative and hypnotic drugs may be screened on the basis of the mechanism of sedation and hypnosis, and may also be screened via animal model means.
Screening sedative and hypnotic drugs via animal model means may suffer from heavy workload, long time, high costs and unclear sedative and hypnotic working mechanism, but the experimental results of the same is more reliable.
Currently, animal models and methods for screening sedative and hypnotic drugs include: (1) general behavior observation; (2) voluntary action observation; (3) elongation of the sleep time under pentobarbital sodium; (4) experimentations with pentobarbital sodium doses below the threshold; (5) Wake up to bed experiments with pentobarbital sodium.
The tested drug is proved to be effective in sedation and hypnosis if the following phenomena are observed: (1) voluntary actions of the mice significantly decrease; (2) the time of sleep caused by pentobarbital sodium increases, and the number of mice increases for which are administered pentobarbital sodium below the threshold and fall into sleep, or the mice go back to sleep for which have been administered pentobarbital sodium and wake up subsequently. In the above animal experiments, it is generally required to employ two doses for the tested drug.
Currently, both western medicine and Chinese traditional medicine are used for treating insomnia. Although western medicine has advantages of rapid onset and outstanding efficiency, it may bring prominent toxicity and side effects, and may easily cause drug resistance and drug dependence. Chinese traditional medicine has lower toxicity and side effects, unlikely brings drug resistance and drug dependence, however, it has slow onset and the effect thereof is not as significant as western medicine. Therefore, currently there are still demands for developing drugs for treating insomnia with good therapeutic effects, low toxicity and little side effects.